Sapphire embedded in protective equipment can improve intelligence, sapphire embedded in jewelry can increase health, and emerald embedded in weapons or wings can increase critical strike damage. In order to improve critical strike damage, wizards should use emeralds on weapons and wings, topaz on defense to improve intelligence, and sapphire on jewelry to increase health.
In addition to emeralds and sapphires needed by every profession, topaz may be regarded as a gem completely belonging to wizards.